Motion estimation is a widely used technique in image processing to find or estimate motion in a set of images. For example, for two 2-dimensional images, in order to estimate motion between these two images, a Sum of Absolute Differences (SAD) or another equivalent calculation is able to be applied on an m×n matching area with a search range of +/−k and +/−l in horizontal and vertical directions respectively, and then the position which yields the smallest SAD is able to be found. FIG. 4 illustrates an example of 2-dimensional motion estimation. In some implementations, a mathematical function is applied to an image to assist in determining a contrast level of the image.